Missing emails from one contact

Bizarre occurrence...emails from one specific contact are not visible in the HUB. But when I "search" by contact name, they all appear. It started yesterday.
On Oreo, APB819 build, updated all the new BlackBerry updates except for Calendar and Tasks last week. Working fine except for this one contact...and it started yesterday. Any ideas? Thanks in advance.

So. After going through a bunch of settings to ensure I hadn't missed something, this morning emails "from" and "to" this contact are now appearing. In fact, while composing this response, I received a notification of an email arriving from this contact.
However, the emails from yesterday do not display unless I "search". Bizarre. Let's see what tomorrow brings...

Curious if you changed an email setting to resolve your problem. I'm seeing this issue on two Keyone's. Specific messages do not show in hub. I can go online and see the email from another client. If I search for the email it shows up with others that were missing. I just noticed this in the last week. Likely some update causing it.

I don't believe it was a setting....but it could have been. I could never find "the" setting. One moment no emails, hours later, they arrive....and have been ever since. At first I thought it might have been caused by me putting the contact in "priority email" but , he was not in there. So, bottom line, I've not had this issue since I first reported it two months ago.